This invention relates to a compact, self-contained, low-cost, integrated disposable emergency breathing system. Briefly, the invention provides a single canister containing a protective hood, a multi-stage air purifying chemical filter attached to the hood and a valved mouthpiece complete with attached noseclip, within the hood, all sealed within the canister until opened for use. When opened, the hood is drawn about an individual's head and breathing is effected through the mouthpiece. The multi-stage filter is designed to filter toxic polar organic gases, convert carbon monoxide to carbon dioxide and, as an alternative, oxygen, and provide filtered breathable air for life support for a period of time, for example, in excess of 10 minutes.
While conventional personal emergency breathing systems have been designed for use in fires and have addressed the problem of removing carbon monoxide and other toxic gases, i.e., cyanides, benzines and the like, they fail to provide a low-cost, one-piece system that integrates a protective hood, mouthpiece and filter in a single compact canister. In such conventional systems, the hood has been either an incidential independent feature of the filter system or has been attached in a separate package to be used or not used by choice. Such hoods have invariably been of a bulky design generally incorporating a solid heat-resistant material forming the main part of the body of the hood, severely restricting two-way communication, and provided with a transparent window of a size which substantially restricts vision and is subject, as a consequence of its limited area, to fogging. Such a design requires the hood to be packed and carried separately.
Prior art emergency breathing systems typically exhaust exhaled gases via a one-way valve to the atmosphere, or back into the filter via the mouth or mouth/nose piece. Consequently, prior art systems have required a rubber/plastic face forming a nose/mouth cover or a mouthpiece and noseclip. These devices are not efficient, particularly when used on bearded or children's faces. Similarly, mouthpieces with a separate noseclip are inconvenient and, unless placed properly on the nose, are subject to being easily dislodged and lost
Prior art systems are often bulky, sometimes require sizing for fitting particular individuals, and generally are not conducive to easy or practical day-to-day carriage or storage. Prior art systems also have employed a variety of fitting methods generally relying on multiple or single-strap arrangements requiring individual adjustment to ensure a proper airtight fit to the individual user. In an emergency or panic situation, such methods are time-consuming and sometimes confusing to use, especially in the case of multiple-strap arrangements. Certain prior art systems do not provide a protective hood or face mask and are complicated in design or use or both. Additionally, such systems are expensive to manufacture, do not lend themselves to a low retail cost, and hence are effectively precluded from a cost standpoint from prepositioning in the necessary numbers in populated areas.
In light of the failings of conventional systems as described above, and according to the present invention, there is provided a simple to use, one-time use, low-cost, compact personal emergency breathing system complete with an integral transparent hood, mouthpiece and passive chemical filter, all housed in a single, easy to carry, compact, unobtrusive canister and able to provide, when used, life support for a period of time sufficient to enable the user to escape from an area containing toxic or noxious gases, such as smoke from a fire.
Generally, the disposable emergency breathing system of the present invention provides a canister comprised of a body housing a filtration unit or stage containing filtering material, a hood and a mouthpiece complete with an attached noseclip, the housing being closed at one end by a cover. The end of the body opposite the cover has at least one air inlet aperture normally sealed by a plastic air-tight push fit seal or a removable adhesive metallic foil, whereby the air inlet to the canister and filtering material is normally closed when the system is not in use. The filtering material is preferably disposed in layered form within the body of the canister and preferably comprises a layer each of activated charcoal granules, a dessicant and a catalyst for the catalyzation of carbon monoxide to carbon dioxide, each layer being separated by an electrostatically charged fabric filter for collecting particulate matter. Also, a layer of lithium peroxide may comprise a fourth layer for converting carbon dioxide to oxygen. Thus, the layered filtering material is disposed within the body of the canister in a manner such that, when the air inlet aperture or apertures are uncovered, air will flow through the apertures and through the charcoal granules, dessicant and catalyst, preferably in that order, and also through the electrostatically charged filters.
Between the filtering material and the cover for the canister, there is provided a mouthpiece connected to a plenum sealingly secured about the margins of the canister body for receiving filtered air from the filtration stage for transmission to the mouthpiece. The mouthpiece contains a one-way inhalation check valve and at least one one-way exhalation check valve, preferably complete with a small integral whistle. Additionally, the mouthpiece preferably carries a noseclip pivotal between a stored position within the canister and a use position pivoted away from the mouthpiece. The mouthpiece and noseclip are enclosed within a wholly transparent hood, likewise sealingly secured about its margins to the canister body. Thus, the mouthpiece, noseclip and hood are secured within the canister body between the filtration stage and the cover when the system is stored and not in use.
To use the system, the mouthpiece carrying the noseclip and the hood are deployed by removing the cover of the canister. The hood and mouthpiece with noseclip are then automatically extended from the canister body. The plastic push fit seal or adhesive-backed metallic foil is also removed to expose the air inlet aperture or apertures and hence the filtration stage to ambient air. The hood has an opening for drawing it about a user's head, the opening preferably having an elastic closure or draw band for drawing and substantially sealing the opening about the individual's neck. With the mouthpiece inside the hood, the individual may then place the mouthpiece in his/her mouth and swing the noseclip from its stored position into a use position about the nose whereby normal breathing may be maintained. Upon inhalation, air entering the canister through the air inlet aperture flows through the filtering material into the plenum and passes through the one-way inhalation check valve to the mouthpiece. Upon exhalation, air flows from the individual's mouth into the mouthpiece and through the exhalation check valve(s), one of which preferably supports an integral whistle, into the hood, the inhalation valve being closed, by virtue of its design, during exhalation. By flowing exhalation air into the hood, a positive pressure within the hood is established. Consequently, the noxious and toxic air, smoke particles and the like cannot enter the hood through the draw band or elasticized hood opening, notwithstanding that a complete seal is not formed between the hood opening and the individual's neck.
The filter stage of the invention is designed to remove toxic/organic gases, thereby affording life support and protection against asphyxiation in order to allow a panic-free evacuation from a typical fire. The transparent hood and mouthpiece of the invention are provided in one size which fits all individuals. Particularly, the transparent hood envelops the individual's entire head and is substantially sealed around the neck, thereby protecting the individual's eyes against the effects of smoke and preventing inhalation of toxic gases. In doing so, the hood also provides unrestricted visibility.
As aforementioned, the mouthpiece is provided with one-way inhalation and exhalation valves. The valves are arranged so that air drawn through the filtration stage and inhaled through the mouthpiece does not, upon exhalation, flow back through the filter. Rather, exhaled air is exhausted from the mouthpiece through the exhalation valve or valves into the interior of the above-described hood. In this way, the hood has a slight positive pressure whereby external noxious and toxic gases at ambient pressure are unable to enter the hood even if the neck seal is incomplete or the hood is damaged. Exhaled gases within the hood are thus released at a natural rate through the neck seal. Conversely, the exhalation valve or valves close upon inhalation, thus preventing backflow of exhaled air within the hood into the mouthpiece or filtration stage.
In a preferred embodiment according to the present invention, there is provided a personal emergency breathing system comprising a canister having a body with an opening and a cover releasably secured to the canister body for closing the opening, material within the body of the canister for filtering air, the body having an air inlet for directing air through the filtering material, a mouthpiece connected to the canister for receiving filtered air from the filtering material, a hood connected to the canister and enveloping the mouthpiece, the mouthpiece and hood being disposed in the canister adjacent the opening and between the cover and the filtering material whereby, upon removal of the cover, the hood and mouthpiece are deployable from the canister, the hood having an opening for receiving an individual's head and neck. First and second one-way valves are disposed between the mouthpiece and the filtering material, the first valve enabling filtered air to be drawn from the filtering material into the mouthpiece and preventing backflow of exhaled air into the filtering material, the second valve enabling exhaled air for flow into the hood and preventing backflow thereof through the second valve to the mouthpiece.
In a further preferred embodiment according to the present invention, there is provided a personal emergency breathing system comprising a canister having a body with an opening and a cover releasably secured to the canister body for closing the opening, an air filtration unit disposed within the body of the canister, the body having an air inlet for directing air through the filtration unit and means for sealing the air inlet to prevent ingress of air into the filtration unit during non-usage of the system and enabling air to flow through the air inlet and the filtration unit during usage of the system. A mouthpiece is provided connected to the canister for receiving filtered air from the filtering material. A hood is connected to the canister and envelops the mouthpiece, the hood having an opening for receiving an individual's head and neck. The mouthpiece and hood are disposed in the canister adjacent the canister opening and between the cover and the filtration unit whereby, upon removal of the cover, the hood and mouthpiece are deployable from the canister. Also provided are means including portions of the mouthpiece and the hood for hermetically sealing the mouthpiece and hood portions about the body opening thereby hermetically sealing the filtration unit within the canister body during non-use of the system and enabling only air flowing into the air inlet and through the filtration unit to flow to the mouthpiece during use thereof.
Some of the unique features of the invention and its objects include: (1) in its unused form, the multi-stage filter chemicals are protected and their purity maintained within the sealed airtight lower section of the canister; (2) the aforedescribed transparent hood and mouthpiece complete with the described valve system and, preferably also a noseclip, are disposed within the upper section of the canister which is normally closed by means of a "twist-off" cap/lid; (3) when in use, multiple small apertures or, in the case of a single plastic push-type seal, a large single aperture in the lower bottom of the canister are provided to allow polluted air to be drawn into and through the filter section and when not in use, are covered and made airtight by a removable adhesive metal foil seal or a single plastic-type seal which maintains the airtight integrity of the canister body and particularly the filtration stage; (4) the "twist-off" lid is designed to ensure positive removal when twisted or turned in either direction by a sloped ramp at the extremities of the retaining groove thereby ensuring that the lid will separate/eject cleanly from the container when fully twisted in either direction without the risk of becoming jammed; (5) the hood material is heat-resistant up to 900.degree. F. and is light, fully transparent, does not restrict the passage of voice communications or sound, and is readily amenable to folding and packing into the upper section of the canister; (6) the neck aperture of the hood is elasticized or provided with a "draw tape" and clearly marked by a highly visible strip of color; (7) by providing a "one-size-fits-all" hood design, children, adults, bearded or beardless individuals, or individuals wearing optical glasses can be accommodated; (8) the casing material is impregnated with a luminescent material, thus providing a means of easy location and identification in the dark; (9) the system has an extended shelf life, is disposable, extremely low-cost, of unitized construction and has sufficient air filtration capacity, e.g., in excess of ten minutes, to enable individuals to escape areas containing polar or non-polar noxious or toxic gases; and (10) an exhaust valve is provided with a whistle to alert potential rescuers to the location of the individual using the present system and which whistle may be activated by sharp exhalation.
These and further objects and advantages of the present invention will become more apparent upon reference to the following specification, appended claims and drawings.